When treating Type I DCS, what is the proper action if symptoms resolve during the 15-minute stop at 50'?

The appropriate action when treating Type I Decompression Sickness (DCS) is to increase the 50' oxygen stop from 15 to 30 minutes if symptoms resolve during the 15-minute stop. This approach serves to provide the diver with additional time breathing oxygen at a depth where the partial pressure of oxygen is increased, which facilitates the elimination of inert gas bubbles formed in the body during the dive.

Oxygen is beneficial in treating DCS as it helps reduce symptoms and promotes a more effective absorption of bubbles and better tissue perfusion. Extending the duration at this depth allows for a more thorough decompression process, minimizing the risk of return of symptoms upon further ascent.

Continuing normal decompression without changes may not provide the diver with the extra therapeutic benefits needed if symptoms have shown improvement, as they may still require additional time at the elevated oxygen levels. Conversely, ascending to a depth of 40' or immediately compressing to the surface would not allow for the needed oxygen therapy and could put the diver at risk of worsening their condition.